The _CrtSetDumpClient function allows the application to hook its own function to dump objects stored in _CLIENT_BLOCK memory blocks into the C run-time debug memory dump process. As a result, every time a debug dump function such as _CrtMemDumpAllObjectsSince or _CrtDumpMemoryLeaks dumps a _CLIENT_BLOCK memory block, the application's dump function is called as well. _CrtSetDumpClient provides an application with an easy method for detecting memory leaks and validating or reporting the contents of data stored in _CLIENT_BLOCK blocks. When _DEBUG is not defined, calls to _CrtSetDumpClient are removed during preprocessing.

The _CrtSetDumpClient function installs the new application-defined dump function specified in dumpClient and returns the previously defined dump function. An example of a client block dump function is as follows:

The userPortion argument is a pointer to the beginning of the user data portion of the memory block and blockSize specifies the size of the allocated memory block in bytes. The client block dump function must return void. The pointer to the client dump function that is passed to _CrtSetDumpClient is of type _CRT_DUMP_CLIENT, as defined in Crtdbg.h: